Method of manufacturing impeller for centrifugal blower

Abstract

A resinous blade-supporting rotator is prepared to rotate around a rotational axis. The blade-supporting rotator has rotator weld parts including rotator weld surfaces formed on one side surface in the axial direction. A plurality of resinous blades are disposed annularly around the axis. The plurality of resinous blades have hollow spaces formed in the blade interiors, and blade weld parts with blade weld surfaces. The blade weld surfaces and the rotator weld surfaces are inclined with respect to each other when facing each other in the axial direction. An axial pressure load is applied to opposite axial ends of the blade-supporting rotator so as to compress the blades in the axial direction such that the blade weld surfaces and the rotator weld surfaces are no longer inclined with respect to each other. The blade weld surfaces are fixed to the rotator weld surfaces by laser welding.

What is claimed is: 
     
       1. A method of manufacturing an impeller for a centrifugal blower comprising:
 preparing a blade-supporting rotator that is resinous to rotate around a rotational axis, the blade-supporting rotator having rotator weld parts including rotator weld surfaces formed on one side surface in the axial direction; 
 disposing a plurality of resinous blades annularly around the axis, the plurality of resinous blades having hollow spaces formed in the blade interiors, 
 the blades having blade weld parts on which are formed blade weld surfaces inclined with respect to the rotator weld surfaces in a state in which the blade weld parts are disposed to face the rotator weld surfaces in the axial direction; 
 applying an axial pressure load to opposite axial ends of the blade-supporting rotator so as to compress the blades in the axial direction such that the blade weld surfaces are no longer inclined with respect to the rotator weld surfaces; and 
 fixing the blade weld surfaces to the rotator weld surfaces by laser welding, the blade weld parts being disposed to face the rotator weld surfaces in the axial direction. 
 
     
     
       2. The method of manufacturing an impeller according to  claim 1 , wherein
 each blade weld surface is inclined at an angle of 0.5 degrees to 2.5 degrees with respect to a respective one of the rotator weld surfaces prior to the applying of the axial pressure load. 
 
     
     
       3. The method of manufacturing an impeller according to  claim 2 , wherein
 prior to the applying of the axial pressure load, each blade weld surface is inclined to be closer to the respective one of the rotator weld surfaces as the blade weld surface is oriented in a direction substantially opposite a direction in which an axially central portion of the blade protrudes orthogonally in the axial direction by bending the blade during the applying of the axial pressure load. 
 
     
     
       4. The method of manufacturing an impeller according to  claim 3 , wherein
 each of the plurality of blades has a first blade surface part, and a second blade surface part attached to the first blade surface part to form the hollow space with the first blade surface part, wherein 
 each blade weld part is formed to extend from the blade-supporting rotator side end of the first blade surface part toward the second blade surface part, and 
 each blade weld surface is inclined to be closer to the respective one of the rotator weld surfaces as the blade weld surface is oriented toward the second blade surface part prior to the applying of the axial pressure load. 
 
     
     
       5. The method of manufacturing an impeller according to  claim 4 , wherein
 a groove or slit is formed in each blade weld part. 
 
     
     
       6. The method of manufacturing an impeller according to  claim 4 , wherein
 each of the plurality of blades has a blade flat surface configured and arranged to be parallel to the respective one of the rotator weld surfaces and disposed at a position axially farther away from the rotator weld surface than the portion of the blade weld surface in proximity to the rotator weld surface, the blade flat surface being formed in the blade weld part in addition to the blade weld surface to be adjacent to the blade weld surface in a state in which the blade weld part is disposed to face the rotator weld surface in the axial direction, and 
 a groove or slit is formed to correspond to a boundary between the blade weld surface and the blade flat surface. 
 
     
     
       7. A method of manufacturing an impeller for a centrifugal blower comprising:
 preparing a blade-supporting rotator that is resinous to rotate around a rotational axis, the blade-supporting rotator having rotator weld parts including rotator weld surfaces formed on one side surface in the axial direction; 
 disposing a plurality of resinous blades annularly around the axis, the plurality of resinous blades having hollow spaces formed in the blade interiors, the blades having blade weld parts on which are formed blade weld surfaces; 
 the rotator weld surfaces being inclined with respect to the blade weld surfaces in a state in which the rotator weld parts are disposed to face the blade weld surfaces in the axial direction; 
 applying an axial pressure load to opposite axial ends of the blade-supporting rotator so as to compress the blades in the axial direction such that the rotator weld surfaces are no longer inclined with respect to the blade weld surfaces; and 
 fixing the blade weld surfaces to the rotator weld surfaces by laser welding, the blade weld parts being disposed to face the rotator weld surfaces in the axial direction. 
 
     
     
       8. The method of manufacturing an impeller according to  claim 7 , wherein
 the rotator weld surfaces are inclined at an angle of 0.5 degrees to 2.5 degrees with respect to the blade weld surfaces prior to the applying of the axial pressure load. 
 
     
     
       9. The method of manufacturing an impeller according to  claim 7 , wherein
 prior to the applying of the axial pressure load, the rotator weld surfaces are inclined to be closer to the blade weld surfaces as the rotator weld surfaces are oriented in a direction substantially opposite a direction in which axially central portions of the blades protrude orthogonally in the axial direction by bending the blades during the applying of the axial pressure load. 
 
     
     
       10. The method of manufacturing an impeller according to  claim 7 , wherein
 the blades include first blade surface parts, and second blade surface parts attached to the first blade surface parts to form the hollow spaces with the first blade surface parts, 
 the blade weld parts are formed to extend from the blade-supporting rotator side ends of the first blade surface parts toward the second blade surface parts, and 
 the rotator weld surfaces are inclined to be closer to the blade weld surfaces as the rotator weld surfaces are oriented toward the second blade surface parts prior to the applying of the axial pressure load. 
 
     
     
       11. The method of manufacturing an impeller according to  claim 7 , wherein
 a groove or slit is formed in each of the blade weld parts. 
 
     
     
       12. The method of manufacturing an impeller according to  claim 7 , wherein
 a rotator flat surface is formed in each of the rotator weld parts in addition to the rotator weld surface to be adjacent to the rotator weld surface in a state in which the rotator weld parts are disposed to face the blade weld surfaces in the axial direction, the rotator flat surfaces being parallel to the blade weld surfaces and being disposed at positions axially farther away from the blade weld surfaces than the portions of the rotator weld surfaces in proximity to the blade weld surfaces, and 
 a groove or slit is formed in each of the blade weld parts to correspond to a boundary between the rotator weld surfaces and the rotator flat surfaces.